﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Ahao.Algorithm.Secondary
{
    /// <summary>
    /// 36. 有效的数独
    /// </summary>
    public class IsValidSudoku
    {
        public bool Method(char[][] board)
        {
            int[,] rows = new int[9, 9];
            int[,] columns = new int[9, 9];
            int[,,] subboxes = new int[3, 3, 9];
            for (int i = 0; i < 9; i++)
            {
                for (int j = 0; j < 9; j++)
                {
                    char c = board[i][j];
                    if (c != '.')
                    {
                        int index = c - '0' - 1;
                        rows[i, index]++;
                        columns[j, index]++;
                        subboxes[i / 3, j / 3, index]++;
                        if (rows[i, index] > 1 || columns[j, index] > 1 || subboxes[i / 3, j / 3, index] > 1)
                        {
                            return false;
                        }
                    }
                }
            }
            return true;
        }
    }
}
